282 lines
8.1 KiB
GLSL
282 lines
8.1 KiB
GLSL
[vertex]
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layout(location = 0) in highp vec4 vertex_attrib;
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layout(location = 4) in vec2 uv_in;
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out vec2 uv_interp;
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out vec2 pos_interp;
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void main() {
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uv_interp = uv_in;
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gl_Position = vertex_attrib;
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pos_interp.xy = gl_Position.xy;
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}
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[fragment]
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in vec2 uv_interp;
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in vec2 pos_interp;
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uniform sampler2D source_diffuse; //texunit:0
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uniform sampler2D source_normal_roughness; //texunit:1
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uniform sampler2D source_depth; //texunit:2
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uniform float camera_z_near;
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uniform float camera_z_far;
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uniform vec2 viewport_size;
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uniform vec2 pixel_size;
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uniform float filter_mipmap_levels;
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uniform mat4 inverse_projection;
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uniform mat4 projection;
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uniform int num_steps;
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uniform float depth_tolerance;
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uniform float distance_fade;
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uniform float curve_fade_in;
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layout(location = 0) out vec4 frag_color;
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vec2 view_to_screen(vec3 view_pos, out float w) {
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vec4 projected = projection * vec4(view_pos, 1.0);
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projected.xyz /= projected.w;
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projected.xy = projected.xy * 0.5 + 0.5;
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w = projected.w;
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return projected.xy;
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}
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#define M_PI 3.14159265359
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void main() {
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vec4 diffuse = texture(source_diffuse, uv_interp);
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vec4 normal_roughness = texture(source_normal_roughness, uv_interp);
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vec3 normal;
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normal = normal_roughness.xyz * 2.0 - 1.0;
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float roughness = normal_roughness.w;
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float depth_tex = texture(source_depth, uv_interp).r;
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vec4 world_pos = inverse_projection * vec4(uv_interp * 2.0 - 1.0, depth_tex * 2.0 - 1.0, 1.0);
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vec3 vertex = world_pos.xyz / world_pos.w;
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vec3 view_dir = normalize(vertex);
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vec3 ray_dir = normalize(reflect(view_dir, normal));
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if (dot(ray_dir, normal) < 0.001) {
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frag_color = vec4(0.0);
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return;
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}
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//ray_dir = normalize(view_dir - normal * dot(normal,view_dir) * 2.0);
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//ray_dir = normalize(vec3(1, 1, -1));
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////////////////
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// make ray length and clip it against the near plane (don't want to trace beyond visible)
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float ray_len = (vertex.z + ray_dir.z * camera_z_far) > -camera_z_near ? (-camera_z_near - vertex.z) / ray_dir.z : camera_z_far;
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vec3 ray_end = vertex + ray_dir * ray_len;
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float w_begin;
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vec2 vp_line_begin = view_to_screen(vertex, w_begin);
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float w_end;
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vec2 vp_line_end = view_to_screen(ray_end, w_end);
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vec2 vp_line_dir = vp_line_end - vp_line_begin;
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// we need to interpolate w along the ray, to generate perspective correct reflections
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w_begin = 1.0 / w_begin;
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w_end = 1.0 / w_end;
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float z_begin = vertex.z * w_begin;
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float z_end = ray_end.z * w_end;
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vec2 line_begin = vp_line_begin / pixel_size;
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vec2 line_dir = vp_line_dir / pixel_size;
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float z_dir = z_end - z_begin;
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float w_dir = w_end - w_begin;
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// clip the line to the viewport edges
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float scale_max_x = min(1.0, 0.99 * (1.0 - vp_line_begin.x) / max(1e-5, vp_line_dir.x));
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float scale_max_y = min(1.0, 0.99 * (1.0 - vp_line_begin.y) / max(1e-5, vp_line_dir.y));
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float scale_min_x = min(1.0, 0.99 * vp_line_begin.x / max(1e-5, -vp_line_dir.x));
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float scale_min_y = min(1.0, 0.99 * vp_line_begin.y / max(1e-5, -vp_line_dir.y));
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float line_clip = min(scale_max_x, scale_max_y) * min(scale_min_x, scale_min_y);
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line_dir *= line_clip;
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z_dir *= line_clip;
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w_dir *= line_clip;
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// clip z and w advance to line advance
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vec2 line_advance = normalize(line_dir); // down to pixel
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float step_size = length(line_advance) / length(line_dir);
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float z_advance = z_dir * step_size; // adapt z advance to line advance
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float w_advance = w_dir * step_size; // adapt w advance to line advance
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// make line advance faster if direction is closer to pixel edges (this avoids sampling the same pixel twice)
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float advance_angle_adj = 1.0 / max(abs(line_advance.x), abs(line_advance.y));
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line_advance *= advance_angle_adj; // adapt z advance to line advance
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z_advance *= advance_angle_adj;
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w_advance *= advance_angle_adj;
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vec2 pos = line_begin;
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float z = z_begin;
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float w = w_begin;
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float z_from = z / w;
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float z_to = z_from;
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float depth;
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vec2 prev_pos = pos;
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bool found = false;
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float steps_taken = 0.0;
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for (int i = 0; i < num_steps; i++) {
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pos += line_advance;
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z += z_advance;
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w += w_advance;
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// convert to linear depth
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depth = texture(source_depth, pos * pixel_size).r * 2.0 - 1.0;
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#ifdef USE_ORTHOGONAL_PROJECTION
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depth = ((depth + (camera_z_far + camera_z_near) / (camera_z_far - camera_z_near)) * (camera_z_far - camera_z_near)) / 2.0;
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#else
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depth = 2.0 * camera_z_near * camera_z_far / (camera_z_far + camera_z_near - depth * (camera_z_far - camera_z_near));
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#endif
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depth = -depth;
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z_from = z_to;
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z_to = z / w;
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if (depth > z_to) {
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// if depth was surpassed
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if (depth <= max(z_to, z_from) + depth_tolerance) {
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// check the depth tolerance
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found = true;
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}
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break;
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}
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steps_taken += 1.0;
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prev_pos = pos;
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}
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if (found) {
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float margin_blend = 1.0;
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vec2 margin = vec2((viewport_size.x + viewport_size.y) * 0.5 * 0.05); // make a uniform margin
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if (any(bvec4(lessThan(pos, -margin), greaterThan(pos, viewport_size + margin)))) {
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// clip outside screen + margin
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frag_color = vec4(0.0);
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return;
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}
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{
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//blend fading out towards external margin
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vec2 margin_grad = mix(pos - viewport_size, -pos, lessThan(pos, vec2(0.0)));
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margin_blend = 1.0 - smoothstep(0.0, margin.x, max(margin_grad.x, margin_grad.y));
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//margin_blend = 1.0;
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}
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vec2 final_pos;
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float grad;
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grad = steps_taken / float(num_steps);
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float initial_fade = curve_fade_in == 0.0 ? 1.0 : pow(clamp(grad, 0.0, 1.0), curve_fade_in);
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float fade = pow(clamp(1.0 - grad, 0.0, 1.0), distance_fade) * initial_fade;
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final_pos = pos;
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#ifdef REFLECT_ROUGHNESS
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vec4 final_color;
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// if roughness is enabled, do screen space cone tracing
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if (roughness > 0.001) {
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///////////////////////////////////////////////////////////////////////////////////////
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// use a blurred version (in consecutive mipmaps) of the screen to simulate roughness
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float gloss = 1.0 - roughness;
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float cone_angle = roughness * M_PI * 0.5;
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vec2 cone_dir = final_pos - line_begin;
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float cone_len = length(cone_dir);
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cone_dir = normalize(cone_dir); // will be used normalized from now on
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float max_mipmap = filter_mipmap_levels - 1.0;
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float gloss_mult = gloss;
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float rem_alpha = 1.0;
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final_color = vec4(0.0);
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for (int i = 0; i < 7; i++) {
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float op_len = 2.0 * tan(cone_angle) * cone_len; // opposite side of iso triangle
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float radius;
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{
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// fit to sphere inside cone (sphere ends at end of cone), something like this:
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// ___
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// \O/
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// V
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//
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// as it avoids bleeding from beyond the reflection as much as possible. As a plus
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// it also makes the rough reflection more elongated.
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float a = op_len;
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float h = cone_len;
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float a2 = a * a;
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float fh2 = 4.0f * h * h;
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radius = (a * (sqrt(a2 + fh2) - a)) / (4.0f * h);
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}
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// find the place where screen must be sampled
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vec2 sample_pos = (line_begin + cone_dir * (cone_len - radius)) * pixel_size;
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// radius is in pixels, so it's natural that log2(radius) maps to the right mipmap for the amount of pixels
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float mipmap = clamp(log2(radius), 0.0, max_mipmap);
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//mipmap = max(mipmap - 1.0, 0.0);
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// do sampling
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vec4 sample_color;
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{
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sample_color = textureLod(source_diffuse, sample_pos, mipmap);
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}
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// multiply by gloss
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sample_color.rgb *= gloss_mult;
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sample_color.a = gloss_mult;
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rem_alpha -= sample_color.a;
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if (rem_alpha < 0.0) {
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sample_color.rgb *= (1.0 - abs(rem_alpha));
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}
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final_color += sample_color;
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if (final_color.a >= 0.95) {
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// This code of accumulating gloss and aborting on near one
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// makes sense when you think of cone tracing.
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// Think of it as if roughness was 0, then we could abort on the first
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// iteration. For lesser roughness values, we need more iterations, but
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// each needs to have less influence given the sphere is smaller
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break;
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}
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cone_len -= radius * 2.0; // go to next (smaller) circle.
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gloss_mult *= gloss;
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}
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} else {
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final_color = textureLod(source_diffuse, final_pos * pixel_size, 0.0);
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}
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frag_color = vec4(final_color.rgb, fade * margin_blend);
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#else
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frag_color = vec4(textureLod(source_diffuse, final_pos * pixel_size, 0.0).rgb, fade * margin_blend);
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#endif
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} else {
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frag_color = vec4(0.0, 0.0, 0.0, 0.0);
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}
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}
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